intracellular pH?

I am not a reseacher, but regarding extracellular PH, the limit of PH
range for health appears to be narrower than first thought according to a
bio-physicist's book, ... guy from Florida. he demonstrates serious
problems away form opitmal 7.45... even 7.42 and 7.48 PH.
I personally (Physics guy) would think internal cell PH would be even
more critical in PARTICULAR REGIONS of the cell, depending on subject
processes. See research book on mitochondria... Mitochodira Biogenesis
and Degradation by the top world researcher.